1. Field of the Invention
The invention relates to a process for the production of a seasoning sauce from bread, which is similar to known soy sauces, and the product therefrom.
2. Description of the Related Art
It is well known to produce soy sauce by a fermentation process in which soybeans, in the form of whole beans or crushed defatted soybeans, and optionally wheat, usually in the form of a roasted coarse meal, and salt are used in varying proportions. Depending upon the kind of malt utilized, an enzyme-containing, fungus-covered substrate, referred to as koji, is initially produced. The koji is then mashed with salt water and subjected to a multi-step fermentation, which comprises a combined hydrolytic process with lactic acid, alcoholic fermentation, and a maturing phase. The fermentation organisms used for the koji production are the hypha fungi of the strain Aspergillus oryzae or A. soyae. The salt-tolerant lactococci Pedoicoccus halophilus, and the yeast Zygosaccharomyces rouxii are preferred for the fermentation phase.
Contrary to previously known methods, where the natural accompanying flora effected the fermentation, modern processes use defined starter cultures. In the case of naturally fermented sauces no mineral acid is employed for accelerating the decomposition of the raw plant materials. This is done exclusively be means of enzymatic hydrolysis effected by the fungal enzymes formed during the koji phase. In recent developments, immobilized enzymes or immobilized microorganisms are used for fermentation. However, when the fermentation period is shortened and the salt content is reduced during processing, particularly during mashing, the taste qualities of the sauces thus achieved are not as good as those produced by the former process. After a prolonged maturing phase (approximately 3 to 6 months) the mash is refined by squeezing, heating, turbidity sedimenting and layer filtration so as to yield the stable ready-to-eat sauce. The traditionally prepared sauce has a dark color and a salty and full, roasty and malty flavor which is somewhat unfamiliar to Western taste.
JP-A-52-76488 describes a process for the production of a seasoning sauce based on protein-containing raw materials such as soybeans, soybean protein, wheat, barley, wheat gluten, corn gluten, fish protein, milk protein, etc., and carbohydrate-containing raw materials such as sorghum, rice bran, wheat bran, potato, molasses, starch residues, etc., from which a koji is made using suitable koji organisms, particularly Aspergillus soyae and Aspergillus oryzae. The koji is then fermented in a saline solution at temperatures between 30.degree. and-55.degree. C.
In U.S. Pat. No. 4,115,591, a process is described for the production of a koji. A koji fungus is cultivated in a modified koji substrate at a temperature of 20.degree. to 40.degree. C. for 30 to 100 hours in the presence of 0.05 to 8% of a salt of an aliphatic carboxylic acid having up to 4 carbon atoms. The koji substrate is selected from the group consisting of soybeans, defatted soybeans, glutamine, rice, wheat, wheat bran, barley, oats, corn, fish meal and other products. The resulting koji is used for producing fermented food products such as soy sauce, miso and sake, by fermentation in a 22% salt solution at 30.degree. C. for 150 days.
EP-A-417 481 describes a process for the production of a soy sauce by means of fermentation on the basis of a koji produced by fermenting a mixture of comminuted soybeans and wheat by means of a koji culture. The koji is hydrolyzed in aqueous suspension with enzymes obtained during the fermentation with the koji culture, at 45.degree. to 60.degree. C. for 3 to 8 hours, whereupon, after the addition of sodium chloride to obtain a salt content of 15 to 19%, the mixture is subjected to a four to eight week fermentation.
U.S. Pat. No. 3,912,822 describes a process for the production of a protein hydrolyzate, having a high glutamic acid content, which is obtained by adding a glutaminase together with a proteolytic enzyme to a protein-containing staring material such as soybeans or wheat gluten.
Agric. Biol. Chem. 49, 745-750 (1985) describes the growth and respiration coefficient of the fungus Aspergillus oryzae, the fungus being cultivated on a solids substrate. Bread is used as the solids substrate. The resulting koji is not fermented any further.
An object of the present invention is to produce a seasoning sauce similar to soy sauce, but which has a lighter color, a high glutamate content, is less roasty as regards taste and more neutral but harmonious so as to be better adapted to the Western trend of taste and which has the lowest possible salt content. Another object was to shorten the production process to a period of less than 3 months.
It has now been surprisingly found that the problems according to the invention can be solved by use of certain process controls using raw materials not traditionally employed for soy sauce fermentation, namely by using an enzyme-containing, fungus-covered substrate (koji) of divided bread of wheat gluten. According to the invention, the koji is mashed with water that is relatively low in salt and then subjected to fermentation, which is carried out in several steps.